Identifying generalist predators of polyphagous pest species for potential use in conservation biological control in viticulture

Ben Hancock *1, Steve Wratten 1, Travis Glare 1, Cor Vink 2

1 Bio-Protection Research Centre, Lincoln University, PO Box 84, Lincoln, 7647, New Zealand
2 AgResearch Limited, Private Bag 4749, Christchurch, 8140, New Zealand

Biological control is often based on prey-specific predators or parasitoids. They can reduce the pest species’ populations, ideally, without impacting on non-target fauna. In contrast, conservation biological control (CBC) enhances existing ecosystem services through habitat manipulation to improve survival, fecundity, longevity and searching activity of predators or parasitoids. Because CBC manipulates the existing environment and its species interactions there is an opportunity to use polyphagus natural enemies as well as prey-specific ones. By identifying a successful generalist predator that preys upon multiple pest species already present in the vineyards, the negative implications of chemical pesticides could be removed and biodiversity enhanced. Vineyards usually have a dearth of biodiversity compared to other environments in the same 30-50° latitudes. The European earwig (Forficula auricularia), the European harvestmen (Phalangium opilio), and the whirligig mite (Anystis baccarum) are generalists that have been identified as the chief predators of the lightbrown apple moth (Epiphyas postvittana), the predominant invertebrate pest in New Zealand’s largest wine-producing region, Marlborough. The relationship between these predators, E. postvittana and another pest of growing concern, citrophilus mealybug (Pseudococcus calceolariae), was examined. The prey and foraging substrate preferences of these three predators is used to distinguish which are suitable for further investigation for managing vineyard pests through CBC. Outcomes from this study can be transferred to other agricultural and horticultural practices using vineyards as a model system because both of the key pests studied here are harmful in a wide range of crops.

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